Problems installing new pushrods!

I guess I'm not understanding your issue. Yo are setting lifter preload - not lash, right? So the important thing is not the sponginess of the plunger - but the amount of preload you give it. Once the oil pressure comes up they won't be spongy. I don't feel the "no freeplay then 1/2 turn" or whatever works. I can't feel no freeplay reliably and I've been doing this for 3 decades. Leave the intake off, and either go by eye, or use the wire gages as was mentioned. Put the preload on them (.050 is where I'd try to land it) and go.